feat(parser): parse navigation chains after array subscripts

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -8535,9 +8535,24 @@ Expression ArrayExpression(Expression obj): {
     { return expr; }
 }
 
+Expression NavigationStep(Expression base):
+{
+    Expression step = null;
+    String nm = null;
+}
+{
+    (
+        "." nm=RelObjectNameExt() { step = new RowGetExpression(base, nm); }
+        |
+        step = ArrayExpression(base)
+    )
+    { return step; }
+}
+
 Expression PrimaryExpression() #PrimaryExpression:
 {
     Expression retval = null;
+    Expression nxt = null;
     Expression expression = null;
     CastExpression castExpr = null;
     TimezoneExpression timezoneExpr = null;
@@ -8713,6 +8728,12 @@ Expression PrimaryExpression() #PrimaryExpression:
 
     [ LOOKAHEAD(2) retval = ArrayExpression(retval) ]
 
+    // navigation chains, e.g. Redshift SUPER col[0].field[1].sub: field accesses
+    // and subscripts may alternate freely after the primary expression
+    (
+        LOOKAHEAD(2) nxt = NavigationStep(retval) { retval = nxt; }
+    )*
+
     (  LOOKAHEAD(2) "::" type=ColDataType() {
             castExpr = new CastExpression();
             castExpr.setUseCastKeyword(false);

src/test/java/net/sf/jsqlparser/expression/ArrayExpressionTest.java

@@ -30,4 +30,116 @@ void testColumnArrayExpression() throws JSQLParserException {
         assertInstanceOf(ArrayConstructor.class, column.getArrayConstructor());
     }
 
+    @Test
+    void testNavigationAfterSubscript() throws JSQLParserException {
+        // Redshift SUPER navigation: subscript then field access
+        String sqlStr = "SELECT recommendations[0].language_id FROM recs";
+        PlainSelect select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+        SelectItem<?> selectItem = select.getSelectItem(0);
+
+        RowGetExpression rowGet = selectItem.getExpression(RowGetExpression.class);
+        assertNotNull(rowGet);
+        assertEquals("language_id", rowGet.getColumnName());
+        Column column = assertInstanceOf(Column.class, rowGet.getExpression());
+        assertEquals("recommendations", column.getColumnName());
+        assertInstanceOf(ArrayConstructor.class, column.getArrayConstructor());
+    }
+
+    @Test
+    void testAlternatingNavigationChain() throws JSQLParserException {
+        // field accesses and subscripts may alternate freely after the primary expression
+        String sqlStr = "SELECT a.b[0].c[1].d FROM t";
+        PlainSelect select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+        SelectItem<?> selectItem = select.getSelectItem(0);
+
+        RowGetExpression outer = selectItem.getExpression(RowGetExpression.class);
+        assertNotNull(outer);
+        assertEquals("d", outer.getColumnName());
+        ArrayExpression subscript = assertInstanceOf(ArrayExpression.class, outer.getExpression());
+        assertInstanceOf(LongValue.class, subscript.getIndexExpression());
+        RowGetExpression inner =
+                assertInstanceOf(RowGetExpression.class, subscript.getObjExpression());
+        assertEquals("c", inner.getColumnName());
+        Column column = assertInstanceOf(Column.class, inner.getExpression());
+        assertEquals("a", column.getTable().getName());
+        assertEquals("b", column.getColumnName());
+        assertInstanceOf(ArrayConstructor.class, column.getArrayConstructor());
+    }
+
+    @Test
+    void testNavigationFieldNames() throws JSQLParserException {
+        // dotted continuations accept FROM/SELECT/CURRENT and quoted names,
+        // same as ColumnIdentifier's dotted continuation (RelObjectNameExt)
+        PlainSelect select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a[0].from FROM t", true);
+        RowGetExpression rowGet = select.getSelectItem(0).getExpression(RowGetExpression.class);
+        assertEquals("from", rowGet.getColumnName());
+
+        select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a[0].\"quoted field\" FROM t", true);
+        rowGet = select.getSelectItem(0).getExpression(RowGetExpression.class);
+        assertEquals("\"quoted field\"", rowGet.getColumnName());
+    }
+
+    @Test
+    void testNavigationInClauses() throws JSQLParserException {
+        TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT * FROM t WHERE a[0].b = 1", true);
+        TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT * FROM t ORDER BY a[0].b", true);
+    }
+
+    @Test
+    void testNavigationThenCastAndJson() throws JSQLParserException {
+        PlainSelect select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a[0].b::text FROM t", true);
+        CastExpression cast = select.getSelectItem(0).getExpression(CastExpression.class);
+        assertInstanceOf(RowGetExpression.class, cast.getLeftExpression());
+
+        TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a[0].b -> 'x' FROM t", true);
+        TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a.b[1 : 2].c FROM t", true);
+        TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a[0].b[1][2].c FROM t", true);
+    }
+
+    @Test
+    void testNavigationDoesNotSwallowQualifiedColumns() throws JSQLParserException {
+        // the navigation loop must not change how plain qualified columns parse
+        PlainSelect select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a.b FROM t", true);
+        Column column = select.getSelectItem(0).getExpression(Column.class);
+        assertEquals("a", column.getTable().getName());
+        assertEquals("b", column.getColumnName());
+        assertNull(column.getArrayConstructor());
+
+        select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a.b.c FROM t", true);
+        column = select.getSelectItem(0).getExpression(Column.class);
+        assertEquals("a.b.c", column.toString());
+
+        select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a.b[0] FROM t", true);
+        column = select.getSelectItem(0).getExpression(Column.class);
+        assertEquals("a", column.getTable().getName());
+        assertEquals("b", column.getColumnName());
+        assertInstanceOf(ArrayConstructor.class, column.getArrayConstructor());
+
+        // a bracket group after a subscript stays on the ArrayExpression slot,
+        // not on the navigation loop
+        select = (PlainSelect) TestUtils.assertSqlCanBeParsedAndDeparsed(
+                "SELECT a[0]['k'] FROM t", true);
+        ArrayExpression array = select.getSelectItem(0).getExpression(ArrayExpression.class);
+        assertNotNull(array);
+        column = assertInstanceOf(Column.class, array.getObjExpression());
+        assertInstanceOf(ArrayConstructor.class, column.getArrayConstructor());
+    }
+
+    @Test
+    void testMalformedNavigationRejected() {
+        assertThrows(JSQLParserException.class,
+                () -> TestUtils.assertSqlCanBeParsedAndDeparsed("SELECT a[0].* FROM t", true));
+    }
+
 }